The compound with formula . Its conversion with metallic lithium consumes four Li per formula unit and can form iron and two lithium sulfide units; that electron inventory sets an ideal battery capacity.
The sparingly soluble sulfate . Its precipitation can retain lead in anode slime in sulfate-based copper electrorefining, but an adherent layer can also contribute to passivation.
The intermetallic compound , commonly with the L12 structure. In superalloys substitution changes its precise composition.
An ionic compound with the fluorite structure at ordinary conditions.
An ionic compound with the fluorite structure at ordinary conditions.
A boron–carbon ceramic used as a neutron absorber, commonly represented approximately by . neutron capture products and irradiation damage affect its usable lifetime.
An oxide with a perovskite structure. Near room temperature its tetragonal phase has switchable electric polarization and is ferroelectric. Its higher-temperature cubic phase is paraelectric.
The molecule is emitted by volcanism and combustion and can be oxidized into sulfuric acid/sulfate. Direct gas deposition competes with gas-phase and aqueous oxidation. The precursor-gas lifetime and the resulting particle lifetime are different quantities.
A hydrogen-containing zirconium phase that can precipitate from hydrogen-bearing zirconium alloys. Brittle hydride platelets and their orientation affect cracking resistance; their behavior differs from dissolved hydrogen.
A Lewis acid-base adduct in which the ammonia nitrogen lone pair donates into the empty boron-centered acceptor orbital of borane. A coordinate covalent bond links nitrogen and boron.
A heteronuclear diatomic molecule consisting of carbon and sulfur. Its permanent electric dipole moment permits an electric-dipole rotational spectrum. The linear rigid rotor model relates its rotational constant to its reduced mass and bond length.
A salt containing a tetracoordinate positively charged phosphorus centre. Deprotonation of a suitable carbon substituent gives a phosphorus ylide.
A phosphonate with an adjacent ester-bearing carbon that can supply the carbon nucleophile in a Horner–Wadsworth–Emmons olefination.
The compound . Regioselected ring expansion of 2-methylcyclopentanone followed by lactam hydrolysis is a constitutional synthetic disconnection.
In the alpha form, MoCl3 has edge-sharing octahedral layers distorted by Mo–Mo dimer formation. Metal-centred electron pairing contrasts with the more localized d electrons of CrCl3.
The solid empirical compound MoCl2 contains octahedral Mo6 cluster units with inner face-capping chlorides and intercluster outer chloride links. An informative connectivity formula is .
A boron hydride. Many boranes have multicentre bonding, so their composition and cage geometry cannot be reconstructed using only independent ordinary two-centre B–B bonds.
A borane-derived cluster containing skeletal carbon vertices. In a simple neutral count, a CH vertex contributes three skeletal electrons while BH contributes two.
A carborane-derived cage with one or more metal vertices. An external ligand such as cyclopentadienyl is not counted as five additional cage vertices.
A metallacarborane containing a cobalt vertex. CpCo can replace BH in a suitable isolobal skeletal-electron count.
The open-face dianion can bind through its five-membered open face as an , six-electron donor. Capping this face with a metal fragment completes a 12-vertex metallacarborane; two faces can also support a bis(dicarbollide) metal donor.
A closed deltahedral carborane. Thermal conversion of nido precursors may change hydrogen content or cage size as well as carbon positions.
An open carborane cage with the nido skeletal-pair count. Mild alkyne–borane reactions can preserve adjacency of newly incorporated carbon atoms.
, a six-vertex arachno borane with nine skeletal pairs. Bridge deprotonation gives the undecahydrohexaborate anion.
, an arachno borane anion with nine skeletal pairs. A localized BH3-adduct drawing does not describe its lowest-energy fluxional cage adequately.
, the bridge-deprotonated conjugate base of pentaborane(9). Its five-vertex framework has seven skeletal pairs and is nido.
is trigonal bipyramidal at its equilibrium minimum. Its twelve small-amplitude vibrational coordinates transform as under D3h.
A four-membered peroxide ring containing two adjacent oxygen atoms and two carbon atoms. The parent 1,2-dioxetane has formula ; its ground state is normally described as a closed-shell singlet.
A reservoir linked to nitrogen dioxide and nitrate radical by reversible association. Conversion to nitric acid, especially through heterogeneous uptake on wet particles, can remove reactive nitrogen from the gas-phase family.
An organic nitrogen reservoir formed by association of a peroxyacetyl radical with nitrogen dioxide. Thermal dissociation can release reactive nitrogen again; its temperature sensitivity helps distinguish transport through cool air from rapid recycling in warmer air.
The aluminium methyl compound commonly forming with four terminal methyl groups and two electron-deficient methyl bridges. Variable-temperature NMR distinguishes slow and fast site exchange.
Molecular has a trigonal-planar sigma framework and ligand-to-boron pi donation. Association energetics differ from those of aluminium chloride.
A compound with an acidic peroxide group; peroxycarboxylic acids contain and can transfer oxygen to an alkene.
A commonly used epoxidation reagent; its carbons are not incorporated into the alkene-derived epoxide.
A compound containing a carbon-attached group. Organomagnesium addition can generate an anionic nitrogen intermediate whose hydrolysis yields a ketone.
The Z isomer of . A stereospecific Diels–Alder reaction retains the cis relationship between its two nitrile substituents.
, the phenyl-substituted nitrile.
A compound with the grouping . A carboxylate-derived leaving group can be expelled during nucleophilic acyl substitution.
. It can give a persistent low-temperature tetrahedral addition complex with a grignard reagent, allowing methyl-ketone isolation after aqueous work-up under controlled conditions.
The phosphate triester , containing three P–O–C linkages and one terminal P–O group. Terminal and alkoxy P–O bonds must be distinguished.
An compound with approximately tetrahedral phosphorus. Its short, strongly polar P–O bond can be described using ionic contributions and oxygen lone-pair donation into P–R antibonding orbitals, without requiring large phosphorus 3d participation.
A five-membered aromatic heterocycle containing NH and four CH groups. The nitrogen lone pair participates in its six-electron aromatic system.
A pyridine ring bearing carboxylic acid substituents at positions 2 and 5. Removing both acidic protons gives a dianion with a neighbouring N,O chelation site and a remote carboxylate site.
An eight-membered cyclic conjugated system with eight electrons. A planar bond-alternating model has the D4h molecular point group. Constraints on planarity matter when discussing its molecular geometry and electronic stability.
A fluorinated carbon material often written CFx. Fluorination disrupts extended graphitic conjugation and introduces carbon–fluorine bonding.
An organic compound with a carbon–halogen bond. Alkyl, allylic and vinylic attachment differ in geometry and substitution reactivity.
An organohalide with the halogen attached directly to an aromatic ring carbon. Its substitution chemistry differs from an alkyl halide because the C–halogen bond is attached to an sp2 carbon.
, an aryl bromide that can be converted to an aryl grignard reagent. Bromine directs electrophilic aromatic substitution preferentially to the ortho and para positions while deactivating the ring overall.
. magnesium insertion provides a cyclohexyl organometallic reagent, while base-induced elimination provides cyclohexene.
A six-membered alternating boron–oxygen ring, commonly . Three-coordinate boron has a vacant p orbital that accepts oxygen lone-pair donation. This stabilizing delocalization does not imply the same aromaticity or equal bond polarity as benzene.
An organic compound containing a carbon-halogen bond. The bonding environment matters: a vinylic halide has the halogen directly attached to a double-bonded carbon, whereas an allylic halide has it attached to the adjacent saturated carbon.
An aluminium–oxygen compound containing Al–O–Al connectivity, often represented compositionally as . Electron-deficient aluminium can achieve four-coordinate environments through cage assembly and multiply bridging oxygen.
A neutral piano-stool complex , conventionally chromium(0), with 18 valence electrons. arene substitution changes electron density and carbonyl stretching frequencies.
A lithium cuprate conventionally represented as LiCuR₂. Its actual structure can be an aggregate and depends on ligand identity, solvent and salts.
A carbon fragment doubly bonded to a metal in the present organometallic usage. Metal–alkylidene exchange with an alkene underlies olefin metathesis.
An organocopper reagent capable of carbon-group transfer. Suitable organocuprates can favour conjugate addition to an enone over direct addition to its carbonyl.
An allylic organotitanium species that can add its allyl group to a carbonyl compound, furnishing a homoallylic alcohol after hydrolysis.
A four-membered titanium–oxygen–carbon–carbon intermediate in carbonyl olefination. Fragmentation yields a carbon–carbon double bond and a titanium–oxygen product.
A four-membered metallacycle containing titanium and three carbon atoms. Cycloreversion can exchange an alkene and a titanium alkylidene; other eliminations become available with suitable substituents.
The reactive early-metal alkylidene . carbonyl methylenation proceeds through an oxatitanacyclobutane; alkene capture gives a titanacyclobutane. Its oxygen affinity makes ester methylenation feasible.
An oligomeric aluminium–oxygen reagent used to alkylate and ionize metallocene polymerization catalysts.
A three-membered metal–carbon–carbon bonding description obtained in the strong alkene-reduction limit. It emphasizes metal–carbon sigma bonding and reduced internal C–C bond order.
A three-membered metal–carbon–carbon ring description with substantial metal–carbon sigma bonding and reduced alkyne bond order.
A silicon–oxygen framework with ideal fully condensed composition . Each silicon has one organic substituent and three siloxane bridges. Incompletely condensed cages retain silanol groups.
A corner-deficient cage . Removing one silicon corner from a T8 cage leaves three silanol-bearing silicon sites, three further sites adjacent to those, and a unique opposite site: symmetry classes 3:3:1.
A cage represented by a cube of eight silicon vertices with one bridging oxygen on each of twelve edges.
A compound containing a silicon–oxygen double bond, . Ordinary small-substituent silanones are highly reactive; oligomerization to siloxane linkages is favoured over persistence as freely dissolved monomers.
An Si–O–Si linkage, or a compound containing such linkages. Cyclic and polymeric siloxanes have strongly polar bonds and flexible bond angles; their bonding should not be reduced to a dominant oxygen-2p/silicon-3d pi interaction.
The substituent , often abbreviated . Its steric and electronic effects should be separated when interpreting regioselectivity.
An Si–OH group or a compound containing it. Condensation of two silanol groups can form an Si–O–Si bond and water.
A coordination ligand containing deprotonated silanol oxygen, , which binds a metal through oxygen. Three silanol groups on a corner-deficient silsesquioxane can give a facial tridentate trianionic donor set.
An organosilicon compound containing Si–Cl bonds. Hydrolysis can produce silanols, whose condensation builds siloxane linkages.
The isolated molecular form is an ideal trigonal bipyramid with D3h molecular point group symmetry. Its solid-state structures need not consist of the same isolated molecules.
Articles were limited to the first 100 out of 294 total.
